1. Field of the Invention
The present invention relates to a household food processor and more particularly to a microprocessor-based control circuit for controlling energization of the food processor drive motor.
2. Description of the Related Art
It has been traditional for food processors to have mechanical switches which permit two basic operational functions. In the first function, the switch is placed in an xe2x80x9conxe2x80x9d position where the drive motor runs constantly until the switch is removed from the xe2x80x9conxe2x80x9d position. A second switch (or function of the first switch) is a xe2x80x9cmomentaryxe2x80x9d or xe2x80x9cpulsexe2x80x9d operation where the drive motor is energized as long as the switch is held in the xe2x80x9cpulsexe2x80x9d position. This arrangement for controlling the drive motor of a food processor requires the user to closely attend the unit and manually control the xe2x80x9cpulsexe2x80x9d pattern to achieve the desired performance. Since food processors typically do not include any indication of the duration of a manually controlled cycle, the user may have difficulty reproducing a successful cycle.
The typical food processor does not include a safety mechanism related to the feeding chute. Therefore, the motor remains running even when the feeding chute has been removed, for example, to add ingredients.
Further, the typical food processor is a single speed device. The user has no option for altering the rotational speed of the drive motor.
An object of the present invention is to provide a new and improved electronic food processor that permits a user to accurately reproduce a successful food processing cycle.
Another object of the present invention is to provide a new and improved electronic food processor with enhanced convenience and safety features.
An electronic food processor in accordance with the present invention incorporates a microprocessor-based electronic control system which acts as an intelligent interface between the user and the food processor drive motor. The user interacts with the microprocessor-based control system by means of a control panel. The control panel includes a liquid crystal display (LCD), light emitting diode (LED) indicators and contact switches. The LCD and LED indicators provide feedback from the electronic control circuit to the user. The user can select among the various functions using the contact switches located on the control panel.
One of the functions selectable by the user through the keypad is the duration of a given food processing cycle. Restated, the control system permits the user to pre-determine a desired end time for the food processing cycle. When the user has selected a pre-established end time, the microprocessor control circuit causes a time remaining to be displayed on the LCD screen in a count down format. Alternatively, the user may simply start the food processor. In which case, an elapse time is displayed on the LCD in a count up format.
In accordance with another aspect of the invention, the microprocessor based control system is provided with programmed instructions for responding to inputs from the user and sensors on the food processor. The user can select an xe2x80x9cauto-pulsexe2x80x9d function in which the food processor drive motor is automatically cycled on and off for predetermined periods in accordance with the programmed instructions.
Safety of the electronic food processor is enhanced by including a xe2x80x9cpausexe2x80x9d feature that removes energy from the drive motor whenever the feed chute is removed. When the feed chute is replaced, the food processing cycle resumes. A food processing cycle can also be paused by pressing the appropriate key on the control panel.
The food processing capability of the electronic food processor is improved by providing an optional high speed for the drive motor. The high speed function can be activated at any time during food processor operation. Motor control is accomplished electronically by the microprocessor based control system in accordance with the programmed instructions and in response to user and sensor inputs.